WO2019031219A1

WO2019031219A1 - Method for transmitting information in controller and method for detecting abnormality in encoder

Info

Publication number: WO2019031219A1
Application number: PCT/JP2018/027585
Authority: WO
Inventors: 靖啓衣笠; 圭相見
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-08-08
Filing date: 2018-07-24
Publication date: 2019-02-14
Also published as: US11446823B2; CN111032294B; CN111032294A; JP7220353B2; JPWO2019031219A1; US20200171661A1; DE112018003523T5

Abstract

A robot has a motor and processes a workpiece. The robot has: a controller for outputting speed commands and command position information; an encoder; a position sensor for outputting, as a difference signal, the amount of positional displacement of the workpiece W relative to a prescribed position; a servo driver for controlling the motor upon receiving the speed command, an output signal from the encoder, and the difference signal; and a safety unit for detecting abnormalities in the encoder. When the servo driver controls the motor on the basis of the speed command, the output signal, and the difference signal, the servo motor transmits the difference signal to the controller. The controller adds a correction value based on the difference signal to the command position information, generates new command position information, and transmits said new command position information to the safety unit.

Description

Information transmission method of controller and abnormality detection method of encoder

The present disclosure relates to a method for transmitting information of a controller provided in an operating device such as a robot and a method for detecting an abnormality in an encoder.

2. Description of the Related Art An abnormality detection technique related to a failure of an encoder used to detect a rotational position of a motor that drives an output shaft of an operating device such as a robot is conventionally known.

Patent Document 1 discloses that an encoder system is provided with a first encoder that detects rotation of an input shaft of a motor and a second encoder that detects rotation of an output shaft of the motor. Further, Patent Document 1 discloses a technique for determining that any one of these encoders is abnormal when there is a difference of a predetermined value or more in position measurement values detected by these two encoders.

Further, Patent Document 2 discloses a servo system including a safety unit that monitors that a motor is normally controlled. The safety unit according to Patent Document 2 generates a stop signal to the servo driver when the command value or the feedback value received from the servo driver controlling the motor is abnormal.

Patent No. 5675761 gazette Patent No. 5376623 gazette

However, in the drive system (motor) of a general-purpose actuator, there are many in which only a single encoder is provided. Therefore, there is a problem that the technology disclosed in Patent Document 1 can not be applied to these general-purpose motors. Further, even in the case of newly configuring a system according to Patent Document 1, it is necessary to provide a plurality of sensors, which increases the cost.

Also in the technique disclosed in Patent Document 2, when applying to a general-purpose system not having an abnormality detection function, it is necessary to add a new function to the servo driver. Therefore, it is necessary to develop both the servo driver and the safety unit. That is, there is a problem that it takes man-hours.

FIG. 17 is a block diagram showing the configuration of a robot control unit according to the prior art disclosed in Patent Document 2. As shown in FIG. In the robot control unit shown in FIG. 17, the controller 7 outputs a command signal to the servo driver 10. The servo driver 10 generates a current value for driving the motor 4 based on the command signal received from the controller 7 and the detection signal acquired from the encoder 5, and controls the motor 4 based on the current value.

The servo driver 10 generates a command value (motor command value) for comparison processing relating to the rotational position of the motor 4 based on the command signal received from the controller 7 and outputs it to the safety unit 9. Similarly, the servo driver 10 is a value indicating the rotational position of the motor 4 based on the output signal acquired from the encoder 5, the reduction ratio of each axis of the motor 4 and the origin information of the motor 4 (hereinafter simply referred to as origin information) The motor detection value is generated and output to the safety unit 9. Then, in the safety unit 9, the motor command value received from the servo driver 10 and the motor detection value are compared, and the abnormality of the encoder 5 is determined based on the comparison result.

However, when the configuration as shown in FIG. 17 is applied to a general-purpose robot not having the abnormality detection device of the encoder 5, the servo driver 10 of the general-purpose robot normally generates a motor command value and a motor detection value. It does not have the function and the function to output the generated motor command value and motor detection value.

Therefore, it is necessary to newly design a circuit, a program and the like having the generation function and the output function. In addition, it is necessary to have a mechanism (circuit, program, display, etc.) indicating whether or not the additionally designed circuit, program, etc. is functioning properly. That is, there is a problem that it takes time and complexity.

Moreover, when welding a workpiece using the above-mentioned robot, the position to be originally welded may shift due to thermal deformation during welding, or the position of the workpiece may be originally shifted from the correct position. In such a case, welding can not be performed correctly even if the robot is operated according to an operation program that is created before the start of welding and is held by the controller. Therefore, a sensor may be used for the purpose of detecting a positional deviation of a work, and a servo driver may independently control a motor based on information from the sensor.

However, when performing such control in the above-described conventional configuration, the controller side can not know the control information uniquely generated by the servo driver for driving the motor. Therefore, there was a possibility that the abnormality detection of the encoder in the safety unit was not performed correctly. The same problem may occur when the controller transmits a speed command for high response to the servo driver, and the servo driver independently controls the motor based on the speed command.

In order to solve the above problems, the present disclosure provides a controller information transmission method and encoder abnormality detection method in which erroneous detection of an encoder abnormality in a safety unit is less likely to occur when a servo driver independently performs motor control. The purpose is

In order to achieve the above object, according to the information transmission method of the controller of the present disclosure, when the servo driver controls the motor based on the main speed command from the controller and other information other than the output signal from the encoder, Control information on control of a motor generated by another information or a servo driver is transmitted to the controller. Then, the controller generates new command position information based on the received other information or control information, and transmits this to the safety unit, thereby preventing the false detection of the encoder abnormality by the safety unit. . Further, in the encoder abnormality detection method according to the present disclosure, when there is a difference between the detection position information calculated based on the output signal of the encoder and the command position information output from the controller, the encoder has a predetermined value or more. It was decided that it was an anomaly of

Specifically, the information transmission method of the first controller of the present disclosure includes a robot arm and a motor connected to an output shaft of the robot arm, and the controller provided in an actuating device for processing a workpiece. A method of transmitting information, wherein a controller outputs a speed command instructing a rotational position of the motor and command position information indicating a rotational position of the motor according to the speed command, and an operating device detects the rotational position of the motor Encoder, a position sensor that outputs a displacement signal of the workpiece from a predetermined position as a differential signal, a speed command output from the controller, an output signal output from the encoder, and a differential signal output from the position sensor And a driver that controls the drive of the motor based on at least the speed command and the output signal, and an abnormality detection that detects an abnormality in the encoder And when the driver controls the motor based on the speed command, the output signal, and the differential signal, the driver transmits the differential signal to the controller, while the controller transmits the differential signal to the command position information. A correction value obtained by conversion is added to generate new command position information, and new command position information is transmitted to the abnormality detection device.

According to this method, by adding the correction value based on the displacement amount of the work to the command position information transmitted from the controller to the safety unit, the control information of the motor uniquely received by the servo driver can be reflected on the command position information. Therefore, it becomes easy to prevent the erroneous detection of the abnormality of the encoder in the abnormality detection device.

The information transmission method of the second controller of the present disclosure is a method of transmitting information of a controller provided in an operating device for processing a work, including a robot arm and a motor connected to an output shaft of the robot arm. The controller outputs a velocity command for instructing the rotational position of the motor and command position information indicating the rotational position of the motor according to the velocity command, and the actuating device includes an encoder for detecting the rotational position of the motor, and A position sensor that outputs, as a differential signal, a positional displacement amount of the workpiece from the position of the target, a speed command output from the controller, an output signal output from the encoder, and a differential signal output from the position sensor; And a driver for controlling the drive of the motor based on the output signal, and an abnormality detection device for detecting an When the driver controls the motor based on the speed command, the output signal, and the difference signal, the driver generates target position information based on the difference signal and the speed command and transmits it to the controller. The target position information is transmitted to the abnormality detection device as new command position information.

According to this method, by using the target position information generated by the servo driver as the commanded position information, the control information of the motor uniquely received by the servo driver can be reflected on the commanded position information. Prevention of false detection of

A third controller information transmission method of the present disclosure is a controller information transmission method provided in an actuator including a robot arm and a motor connected to an output shaft of the robot arm, the controller being a motor First and second speed commands for specifying the rotational position of the motor and command position information indicating the rotational position of the motor according to the first and second speed commands, and the actuating device detects the rotational position of the motor And the first and second speed commands output from the controller and the output signal output from the encoder, and controlling the driving of the motor based on at least one of the first and second speed commands and the output signal And an abnormality detection device for detecting an abnormality in the encoder, the driver including the first and second speed commands and an output signal from the encoder When controlling the motor based on the driver, the driver transmits control information based on the second speed command to the controller, while the controller converts the control information based on the second speed command into the command position information, and the correction is obtained The values are added to generate new command position information, and the new command position information is transmitted to the abnormality detection device.

According to this method, the control of the motor that the servo driver independently receives by adding the correction value obtained by converting the control information based on the second speed command to the command position information transmitted from the controller to the safety unit Since the information can be reflected on the command position information, it is easy to prevent the erroneous detection of the abnormality of the encoder in the abnormality detection device.

A fourth controller information transmission method of the present disclosure is a controller information transmission method provided in an actuator including a robot arm and a motor connected to an output shaft of the robot arm, the controller being a motor First and second speed commands for specifying the rotational position of the motor and command position information indicating the rotational position of the motor according to the first and second speed commands, and the actuating device detects the rotational position of the motor And the first and second speed commands output from the controller and the output signal output from the encoder, and controlling the driving of the motor based on at least one of the first and second speed commands and the output signal And an abnormality detection device for detecting an abnormality in the encoder, the driver including the first and second speed commands and an output signal from the encoder When controlling the motor on the basis, the driver generates target position information based on the first and second speed commands and transmits it to the controller, while the controller generates new command position information based on the target position information. And transmitting new command position information to the abnormality detection device.

According to this method, the controller generates new command position information based on the target position information generated by the servo driver, and transmits this to the abnormality detection apparatus, thereby controlling the control information of the motor uniquely received by the servo driver. Since the command position information can be reflected, it becomes easy to prevent the erroneous detection of the abnormality of the encoder in the abnormality detection device.

An encoder abnormality detection method according to the present disclosure is an abnormality detection method for detecting an encoder abnormality for detecting a rotational position of a motor that drives an output shaft of an actuator, the actuator detecting an encoder abnormality An abnormality detection device and a speed command for specifying a rotational position of the motor are output, and command position information indicating a rotational position of the motor according to the speed command is detected using any one of the first to fourth information transmission methods. The abnormality detection device further comprises: a controller for transmitting to the controller; and a driver for receiving the speed command output from the controller and the output signal output from the encoder and controlling the driving of the motor based on the speed command and the output signal. An information acquisition step for acquiring command position information from the controller and an output signal from the encoder, and command position information And an abnormality determination step of comparing the detected position information of the motor calculated based on the output signal and determining that the encoder is abnormal if there is a difference between the commanded position information and the detected position information by a predetermined value or more. It is characterized by doing.

According to this method, the abnormality detection device determines the abnormality of the encoder based on the comparison result of the commanded position information received from the controller and the detected position information calculated based on the output signal from the encoder. This makes it possible to detect an abnormality in the encoder without adding a new configuration or function to the driver for detecting an abnormality in the encoder. That is, for example, it is possible to detect an abnormality in the encoder while suppressing the influence on the existing configuration and the existing circuit of a general actuation device (for example, a robot or an external axis).

In the abnormality determination step, the abnormality detection device compensates for the time delay caused due to the delay of the drive control of the motor with respect to the command position information acquired from the controller, and detects the command position information and the time delay compensated. It is preferable to determine the presence or absence of an abnormality of the encoder based on the comparison result with the position information.

As described above, by delaying the command position information used to determine the abnormality of the encoder, it is possible to eliminate the time lag due to the delay of the motor drive control. Therefore, the abnormality detection accuracy of the encoder can be enhanced.

In the abnormality determination step, the abnormality detection device generates an integrated value of the change amount of the command position information output from the controller, and based on the comparison result of the sum of the integrated value and the command position information and the detected position information. It is preferable to determine the presence or absence of abnormality of the encoder.

Thus, the margin in the abnormality determination is increased by adding the integrated value to the command position information used for the abnormality determination of the encoder. Therefore, it is possible to prevent the abnormality detection device from determining that the encoder is abnormal although the encoder is operating normally.

The abnormality detection device preferably determines the presence or absence of an abnormality in the encoder based on the comparison result of the sum of the integrated value and the command position information plus a predetermined threshold value and the detected position information in the abnormality determination step. .

According to this method, by adding a threshold value to the sum of the integrated value and the command position information and comparing it with the detected position information, there is no change in the period command position information, for example, when the operation device is not operating. Even when the differential device performs an unintended operation, an abnormality in the encoder can be detected.

There is further provided a safety circuit for emergency stop of the actuating device, and the controller is configured to transmit an emergency stop signal to the safety circuit in an emergency, and the abnormality detection device is emergency stop from the controller in the abnormality determination step. When it is detected that a signal is output, it is preferable not to determine that the encoder is abnormal even if there is a difference of a predetermined value or more between the command position information and the detection position information.

According to this method, even if there is a difference between the commanded position information and the detected position information after the controller outputs the emergency stop signal, it is not determined that the encoder is abnormal. Therefore, for example, when the controller stops outputting the speed command and the command position information after outputting the emergency stop signal, it is easy to prevent the determination that the encoder is abnormal although the encoder is operating normally. become.

As described above, according to the controller information transmission method of the present disclosure, when the servo driver controls the motor also based on information other than the main speed command from the controller and the output signal from the encoder, the abnormality detection device Is less likely to erroneously detect an encoder error. Further, according to the encoder abnormality detection method of the present disclosure, even when a general-purpose encoder is used, the influence on the existing function and the existing apparatus can be minimized, and the encoder abnormality can be determined.

It is a schematic block diagram of the robot control system concerning a 1st embodiment. It is a block diagram showing composition of a robot control part concerning a 1st embodiment. It is a block diagram showing composition of a safety unit. It is a flowchart which shows the transmission procedure of command position information by a controller. It is a flow chart which shows another transmitting procedure of command position information by a controller. It is a flowchart which shows the abnormality determination method of an encoder. It is a schematic block diagram of the robot control system concerning a 2nd embodiment. It is a block diagram showing composition of a robot control part concerning a 2nd embodiment. It is a flowchart which shows the transmission procedure of command position information by a controller. It is a flow chart which shows another transmitting procedure of command position information by a controller. It is a block diagram which shows the other structural example of a robot control part. It is a figure which shows the relationship between a motor command position and a motor detection position. It is a block diagram which shows the other structural example of a robot control part. It is a figure which shows the relationship between a motor command position and a motor detection position. It is a flowchart which shows the other example of the abnormality determination method of an encoder. It is a figure which shows the relationship of the motor command position at the time of advancing operation | movement which concerns on 3rd Embodiment, and an actual position. It is a figure which shows the relationship of the motor instruction | command position at the time of reciprocation concerning 3rd Embodiment, and an actual position. It is a figure which shows the relationship between a motor command position and a motor detection position. It is a block diagram which shows the structure of the robot control part which concerns on a prior art.

Hereinafter, the present embodiment will be described in detail based on the drawings. The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its applications or its uses.

-First Embodiment-
<Configuration of robot and its control system>
FIG. 1 is a schematic configuration diagram of a robot control system as an actuation device according to the present embodiment. Further, FIG. 2 is a block diagram showing the configuration of the robot control unit 2, and arrows are shown so that the transmission direction of information or a signal can be known. The robot A according to the present embodiment is used to process the workpiece W.

As shown in FIG. 1, the robot A is configured by a robot mechanism unit 1, a robot control unit 2, and an operation unit 3 with a display. A connection cable C is connected between the robot mechanism unit 1 and the robot control unit 2. In addition, in FIG. 1, although information shall be transmitted by wired connection by the connection cable C, a connection form is not limited to wired connection, You may connect by wireless. The connection between each block is also the same.

The robot mechanism unit 1 has a plurality of robot arms 11 and a plurality of joint shafts 12. Each robot arm 11 is attached with a servomotor 4 (hereinafter referred to as a motor 4) for operating the robot arm 11. For example, when the robot A is a vertical articulated six-axis robot, it has six robot arms 11, and six motors 4 are provided to correspond to each robot arm 11. Each motor 4 is attached with an encoder 5 for detecting a rotational position of the motor 4 or an amount of rotation based on the rotational position.

Further, a torch 14 for performing arc welding is provided at the tip of the robot arm 11, and power is supplied from a power supply unit (not shown), and the workpiece W is disposed at a predetermined position on a stage (not shown) Do welding.

In addition, a position sensor 13 for detecting the position of the work W is provided in the robot mechanism unit 1 separately from the robot arm 11. The position sensor 13 may be disposed at a position where the trajectory connecting the welding start place and the welding end place of the workpiece W can be confirmed.

Although not illustrated in FIG. 1, an external shaft driven based on drive control from the robot control unit 2 to the robot mechanism unit 1 is attached to the robot A. The external axis is used in combination with the robot mechanical unit 1 in order to expand the movable range of the robot A. A motor 4 for operating the external shaft is attached to the external shaft. An encoder 5 for detecting a rotational position of the motor 4 or a rotation amount based on the rotational position is attached to the motor 4. That is, the motor 4 is connected to each of the plurality of joint shafts 12 and the external shaft, and the encoder 5 is attached to each motor 4. The type of the external shaft is not particularly limited. For example, the technology according to the present embodiment is applicable to either the slider type or the positioner type, and may be other types.

In the present embodiment, in order to facilitate understanding of the invention, the motor 4 and the encoder 5 using a plurality of joint shafts 12 and the motor 4 and the encoder 5 used for the external shaft are illustrated without distinction (FIG. 1) See) and explain. Therefore, in the following, the term "motor 4" or "encoder 5" refers to both those using a plurality of joint shafts 12 and those using an external shaft. That is, the abnormality detection device and the abnormality detection method of the encoder 5 described below are applied to both the encoder 5 attached to the motor 4 for the plurality of joint shafts 12 and the encoder 5 attached to the motor 4 for the external shaft It is possible.

The encoder 5 is connected to a safety unit 9 and a servo driver 10 described later, and outputs (feedback) the detected signal to the safety unit 9 and the servo driver 10.

The operation unit 3 includes an input unit (not shown) that receives an input operation of the operator of the robot A and a display (not shown). The operation unit 3 communicates with the robot control unit 2 based on an input operation from the operator. Thus, the operator can perform operation setting, operation control, and the like of the robot arm 11 through the operation unit 3. The input unit may be configured by a touch panel, and the display and the input unit may be configured integrally.

The robot control unit 2 includes a controller (for example, CPU) 7, a RAM (Random Access Memory) 8 as a storage unit, a safety unit 9 as an abnormality detection device, a servo driver 10, and a safety circuit (controller) 6. Have. The servo driver 10 is a driver for driving each motor 4. The safety circuit (controller) 6 also shuts off the power supply (not shown) for driving the robot A in response to an emergency stop signal instructing the emergency stop from the safety unit 9. In the present embodiment, the robot control system includes the encoder 5, the robot control unit 2, and the position sensor 13.

The RAM 8 stores a teaching program of the robot A created by the operator using the operation unit 3, function settings of the robot A, and the like.

The controller 7 calculates a speed command (rotation angle of the motor 4 advancing per unit time) based on the teaching program, function setting and the like stored in the RAM 8. Further, the controller 7 outputs the calculated speed command to the servo driver 10 to issue an operation command of the robot A. Similarly, the controller 7 integrates the speed command based on the home position, and outputs the integrated value to the safety unit 9 as command position information. The speed command is calculated based on, for example, the reduction ratio of the robot A, the origin position of the robot A, and the like.

The position sensor 13 is connected to the servo driver 10, and the displacement amount of the workpiece W from a predetermined position, that is, the displacement amount of the workpiece W with respect to the trajectory of the robot arm 11 specified in the operation program is expressed by XYZ coordinates. It transmits to the servo driver 10 as a differential signal represented by a system.

The servo driver 10 generates a current value for driving the motor 4 based on the speed command received from the controller 7, the output signal from the encoder 5, and the difference signal from the position sensor 13 as necessary. Furthermore, the servo driver 10 controls the operation of the robot A by controlling the motor 4 based on the current value.

The safety unit 9 is directly connected to the encoder 5 and the controller 7. Then, the safety unit 9 determines whether the encoder 5 is broken based on the detected position information of the motor 4 calculated based on the output signal received from the encoder 5 and the commanded position information received from the controller 7. Determine

FIG. 3 is a block diagram showing the configuration of the safety unit 9.

As shown in FIG. 3, the safety unit 9 includes a CPU 92 as a determination unit, a RAM 93, an encoder reception unit 94 as a first reception unit, and a DPRAM (Dual Port RAM) 95 as a second reception unit. ing.

The encoder reception unit 94 is connected to the encoder 5 and acquires an output signal from the encoder 5.

The DPRAM 95 is connected to the controller 7 of the robot control unit 2 and acquires command position information output from the controller 7. The command position information is obtained by integration of the speed command output from the controller 7 to the servo driver 10. The command position information acquired by the DPRAM 95 is stored in the RAM 93.

The CPU 92 receives the output signal from the encoder reception unit 94 and calculates detection position information on the current position of the motor 4 using the output signal, the reduction ratio of the robot A, the origin position of the robot A, and the like. And the command position based on command position information and the detection position based on detection position information are compared, and the presence or absence of abnormality of the encoder 5 is confirmed.

In FIG. 3, the CPU 92, the RAM 93, and the DPRAM 95 are connected in the same configuration, and two sets having the same function are provided. This enables parallel processing using two CPUs 92. That is, the same abnormality determination can be performed in duplicate, and the reliability can be further improved as compared with the case of one set.

<Transmission procedure of command position information by controller>
In the present embodiment, in order to correct the positional deviation of the work W, the servo driver 10 controls the motor 4 based on the speed command from the controller 7, the output signal from the encoder 5, and the difference signal from the position sensor 13. Consider the case of controlling

FIG. 4A shows a flowchart of an output procedure of command position information by a controller according to the present embodiment, and FIG. 4B shows a flowchart of another output procedure of command position information.

First, as shown in FIG. 4A, the robot control unit 2 is activated (step ST1). In step ST1, the safety circuit 6, the controller 7, the RAM 8, the safety unit 9, and the servo driver 10 are activated. The position sensor 13 is also activated.

Next, the controller 7 generates a speed command and command position information based on the teaching program and the function setting of the robot A, the origin information, etc. stored in the RAM 8 (step ST2), and gives the servo driver 10 a speed command. Is sent (step ST3).

The servo driver 10 takes in the difference signal from the position sensor 13 (step ST4). The servo driver 10 generates control information for controlling the rotation operation of the motor 4 based on the difference signal, the speed command from the controller 7 and the output signal from the encoder 5 (step ST5). The difference signal is transmitted (step ST6).

The controller 7 converts the received difference signal into the amount of movement R of the corresponding joint axis, that is, the rotation angle of the motor 4 in the clockwise or counterclockwise direction (step ST7). Then, the converted operation amount R is added as a correction value to the command position information generated by the controller 7 itself to generate new command position information (step ST8). Next, the controller 7 transmits the new command position information to the safety unit 9 (step ST9).

On the other hand, in the command position information transmission procedure shown in FIG. 4B, steps ST1 to ST4 are the same as the flow shown in FIG. 4A, but the servo driver 10 sets the differential signal from the position sensor 13 to the movement amount R of the joint axis. Convert (step ST5), and further generate target position information as control information (step ST6). Here, the target position information is a value obtained by adding the operation amount R, the speed command V from the controller, and the initial value I at the time of power on. Further, the servo driver 10 transmits the target position information to the controller 7 (step ST7), and the controller 7 transmits the received target position information as new command position information to the safety unit 9 (step ST8).

4A and 4B, the step in which the servo driver 10 takes in an output signal from the encoder 5 is not shown.

Further, in the flow shown in FIGS. 4A and 4B, each step does not necessarily have to be processed in the order described, but the order may be changed, and if parallel processing is possible, the order or processing of processing may be appropriately performed. You may change the method. For example, in FIGS. 4A and 4B, the process according to step ST4 may be performed before the process according to step ST3 or in parallel with step ST3.

<Abnormal detection method of encoder>
FIG. 5 is a flowchart showing how the safety unit 9 monitors the abnormality of the encoder 5 after the robot control unit 2 starts the robot A and the robot A starts its operation. That is, FIG. 5 shows how the safety unit 9 monitors the abnormality of the encoder 5 when the controller 7 causes the motor 4 to rotate via the servo driver 10.

In step ST1, the controller 7 of the robot control unit 2 starts the robot A, and proceeds to step ST2.

In step ST2, the robot control unit 2 causes the robot A to operate based on the teaching program and the function setting and the like set by the operator via the operation unit 3. Specifically, the controller 7 outputs a speed command to the servo driver 10 and a command position information to the safety unit 9 based on the teaching program and function settings stored in the RAM 8. The servo driver 10 drives the motor 4 based on the speed command received from the controller 7 to operate the joint axis 12 and the external axis of the robot A. The servo driver 10 receives an output signal from the encoder 5 attached to the motor 4 and performs feedback control on the motor 4 based on the difference between the speed command and the output signal. At this time, the output signal from the encoder 5 is also output to the safety unit 9.

In the safety unit 9, when the output signal from the encoder 5 is obtained (ST3), the motor position is calculated (ST4). Specifically, the CPU 92 of the safety unit 9 converts the rotational position (the current position) of the motor 4 based on the output signal acquired from the encoder 5, the reduction ratio of each axis of the motor 4 and the origin information of the motor 4 Make a calculation. The output signal obtained from the encoder 5 is transmitted, for example, in the form of a pulse signal.

Furthermore, the safety unit 9 receives command position information from the controller 7 (ST5), and compares the detected position information on the current position of the motor 4 calculated in ST4 with the command position information from the controller 7 (ST6) ). Specifically, the CPU 92 of the safety unit 9 calculates the rotational position (motor detection value) of the motor 4 calculated based on the output signal from the encoder 5 and the rotational position (motor command value) of the motor instructed from the controller 7 Compare with). The command position information shown in steps ST5 and ST6 also includes new command position information shown in FIGS. 4A and 4B.

If the difference between the motor command value and the motor detection value is equal to or greater than the predetermined value as a result of the comparison (YES in ST7), the CPU 92 determines that the encoder 5 is abnormal, and proceeds to step ST8. On the other hand, if the difference between the motor command value and the motor detection value is less than the predetermined value (NO in ST7), the flow does not determine that the encoder 5 is abnormal, and the flow returns to step ST3.

Specifically, in the drive control of the robot A, the motor 4 is about to move to the position instructed by the controller 7. Therefore, the difference between the motor detection value (detection position information) indicating the rotation position of the motor 4 and the motor command value (command position information) indicating the rotation position commanded by the controller 7 is within the predetermined threshold Pth. It should be. Therefore, when it is determined that the rotational position of the motor based on the motor detection value is separated from the motor command position based on the motor command value by a predetermined position or more, it is determined that the encoder is broken.

In step ST8, the CPU 92 of the safety unit 9 transmits an emergency stop signal to the safety circuit 6. The safety circuit 6 that has received the emergency stop signal shuts off the drive power supply of the robot A, and makes the robot A emergency stop.

As described above, after the controller 7 starts the robot A and causes the robot A to start its operation, the safety unit 9 repeatedly executes the processing of steps ST3 to ST7 and determines that the encoder 5 is abnormal.

As described above, according to the present embodiment, in the abnormality detection of the encoder 5, the safety unit 9 compares the position information directly acquired from the controller 7 with the position information calculated based on the output signal from the encoder 5. An abnormality of the encoder 5 is detected based on the result. Thus, by adding the safety unit 9 to an operating device such as a general-purpose robot that does not have an encoder abnormality detection device, it is possible to detect an abnormality due to a failure of the encoder. Furthermore, at that time, there is no need to make a design change or the like to the components of the existing general-purpose robot such as the servo driver 10, and the operation device or system using a general encoder while suppressing the influence on the existing system. Applicable to Therefore, it is not necessary to indicate to the existing system that the process related to the abnormality determination of the encoder is properly performed, and the process is not complicated.

This point will be described in comparison with the prior art shown in FIG.

When the configuration as shown in FIG. 17 is applied to a general purpose robot not having the abnormality detection device of the encoder 5, the servo driver 10 of the general purpose robot usually generates a motor command value and a motor detection value, There is no function to output the generated motor command value and motor detection value. Therefore, it is necessary to newly design a circuit, a program and the like having the generation function and the output function. In addition, it is necessary to have a mechanism (circuit, program, display, etc.) indicating whether or not the additionally designed circuit, program, etc. is functioning properly. That is, there is a problem that it takes time and complexity. On the other hand, the abnormality detection method and the abnormality detection device according to the present disclosure do not have such a problem.

Further, as described above, since the control information generated to drive the motor 4 from the servo driver 10 is not known on the controller 7 side, the abnormality detection of the encoder 5 is performed based on the command position information generated by the controller 7. In the safety unit 9, there was a risk that the abnormality detection could not be performed correctly.

According to the present embodiment, when the servo driver 10 controls the rotational operation of the motor 4 based on not only the speed command from the controller 7 and the output signal from the encoder 5 but also the difference signal from the position sensor 13 The controller 7 generates new command position information based on the difference signal from the position sensor 13 or the target position information is generated by the servo driver 10 based on the difference signal from the position sensor 13, and the controller 7 As new command position information. As a result, the control information of the motor 4 of the portion uniquely performed by the servo driver 10 can be reflected on the command position information generated by the controller 7. Therefore, it is possible to prevent the erroneous detection of the abnormality of the encoder 5 by the safety unit 9, and maintain the abnormality detection accuracy of the encoder 5.

When the target position information (see step ST6 in FIG. 4B) is generated by the servo driver 10, the control period of the servo driver 10 is shorter than the control period of the controller 7. Control information can be reflected.

In the embodiment, when the difference signal from the position sensor 13 is not used for the rotation control of the motor 4, the servo driver 10 does not transmit the control information to the controller 7, and the command position information generated by the controller 7 is directly transmitted. , And the abnormality detection of the encoder 5 is performed based on the flow shown in FIG.

-Second embodiment-
<Configuration of robot and its control system>
FIG. 6 is a schematic configuration diagram of a robot control system as an actuation device according to the present embodiment. Further, FIG. 7 is a block diagram showing the configuration of the robot control unit 2, and arrows are shown so that the transmission direction of information or a signal can be known.

The robot control system shown in FIG. 6 only omits the position sensor 13 from the robot control system shown in FIG. 1, and the other components and the functions of the respective components are the same as in the first embodiment. Because there is, I omit the explanation.

In addition, although the configuration of the robot control unit 2 shown in FIG. 7 also omits the position sensor 13 from the configuration shown in FIG. 2, the difference from the configuration shown in the first embodiment is the first speed from the controller 7 The command and the second speed command are sent to the servo driver 10.

Among these, the first speed command is the same as the speed command shown in the first embodiment, and the first speed command is the main speed command. On the other hand, in the case where the second speed command performs more responsive control (hereinafter referred to as high response control) on the servo driver 10 side separately from the first speed command created by the controller 7 based on the information of the teaching program. The controller 7 sends a command to the servo driver 10.

Here, high response control will be described. For example, in order to reduce the spatter generated at the time of welding at the welding start point or the like, the robot A may rapidly pull up and return the robot arm 11. When performing the pull-up or pull-down operation, control that the servo driver 10 performs in parallel to normal control corresponds to high responsiveness control. Control of the sudden acceleration / deceleration operation of the robot arm 11 or the like also corresponds to high response control. When such control is performed, if a speed command which is an operation command of the robot A is sent directly from the controller 7, the process of processing the speed command on the side of the servo driver 10 becomes complicated. Therefore, the controller 7 transmits the second speed command to the servo driver 10 in addition to the first speed command, and the servo driver 10 controls the motor 4 by determining the target position in consideration of these two speed commands. .

<Transmission procedure of command position information by controller>
In the present embodiment, as described above, in order to perform high response control of the robot A, the controller 7 transmits the first and second speed commands to the servo driver 10, and the servo driver 10 transmits the first and second speed commands. A case where the motor 4 is controlled based on the 2 speed command and the output signal from the encoder 5 will be considered.

FIG. 8A shows a flowchart of an output procedure of command position information by the controller according to the present embodiment, and FIG. 8B shows a flowchart of another output procedure of command position information.

Of the flows shown in FIGS. 8A and 8B, steps ST1 and ST2 are the same as steps ST1 and ST2 of the flows shown in FIGS. 4A and 4B, and thus the description thereof is omitted.

As shown in FIG. 8A, the controller 7 generates a second speed command for high response control (step ST3), and transmits the first and second speed commands to the servo driver 10 (step ST4). The servo driver 10 generates control information for controlling the rotational operation of the motor 4 based on these speed commands and the output signal from the encoder 5 (step ST5). Next, the servo driver 10 transmits, to the controller 7, information uniquely generated by the servo driver 10, in this case, control information based on the second speed command (step ST6). The controller 7 converts control information based on the second speed command into the movement amount R2 of the joint axis (step ST7), adds the movement amount R2 as a correction value to the command position information generated by itself, and generates a new command. Position information is generated (step ST8), and the new command position information is transmitted to the safety unit 9 (step ST9).

On the other hand, in the transmission procedure of command position information shown in FIG. 8B, steps ST1 to ST4 are the same as the flow shown in FIG. 8A, but target position information is generated as control information uniquely executed by the servo driver 10 (step ST5). ). Here, the target position information is a value obtained by adding the first and second speed commands V1 and V2 and the initial value I at power-on. Further, the servo driver 10 transmits the target position information to the controller 7 (step ST6). Here, the target position information shown in FIG. 8B is a relative value held by the servo driver 10, that is, an amount indicating how much the joint axis moves from the position at a certain point in time. Therefore, the controller 7 adds the integrated value up to that point to the received target position information to convert it into an absolute position, that is, a movement amount from the origin (step ST7), and uses this as new command position information. (Step ST8).

In FIGS. 8A and 8B, the step in which the servo driver 10 takes in an output signal from the encoder 5 is not shown.

Further, in the flow shown in FIGS. 8A and 8B, the steps do not necessarily have to be processed in the order described, but the order may be changed, and if parallel processing is possible, the order or processing of processing may be appropriately performed. You may change the method. For example, in FIGS. 8A and 8B, the process according to step ST3 may be performed before the process according to step ST2 or in parallel with step ST2.

<Abnormal detection method of encoder>
The method of detecting an abnormality in the encoder according to the present embodiment is the same as the method of detecting an abnormality according to the first embodiment shown in FIG. Needless to say, the command position information sent from the controller 7 to the safety unit 9 also includes new command position information shown in FIGS. 8A and 8B.

Also in this embodiment, the safety unit 9 compares the position information directly acquired from the controller 7 with the position information calculated based on the output signal from the encoder 5 in the abnormality detection of the encoder 5 based on the result of comparison. An abnormality in the encoder 5 is detected. Thus, by adding the safety unit 9 to an operating device such as a general-purpose robot that does not have an encoder abnormality detection device, it is possible to detect an abnormality due to a failure of the encoder. Furthermore, at that time, there is no need to make a design change or the like on the components of the existing general-purpose robot such as the servo driver 10, and the influence on the existing system can be reduced. Therefore, it is not necessary to indicate to the existing system that the process related to the abnormality determination of the encoder is properly performed, and the process is not complicated.

According to the present embodiment, when the servo driver 10 controls the rotational operation of the motor 4 based on the two different types of speed commands from the controller 7 and the output signal from the encoder 5, the response for high response is The controller 7 generates new command position information from control information based on the second speed command, or the target position information is generated by the servo driver 10 based on two speed commands, and the controller 7 converts this into an absolute position. New command position information. As a result, the control information of the motor 4 of the portion uniquely performed by the servo driver 10 can be reflected on the command position information generated by the controller 7. For this reason, the erroneous detection of the abnormality of the encoder 5 by the safety unit 9 can be prevented, and the abnormality detection accuracy of the encoder 5 can be maintained.

When the target position information (see step ST6 in FIG. 4B) is generated by the servo driver 10, the control cycle of the servo driver 10 is shorter than the control cycle of the controller 7, so the control responsiveness of the robot A can be improved. .

Further, in the present embodiment, when the controller 7 does not generate the second speed command, the servo driver 10 does not transmit the control information to the controller 7 and transmits the command position information generated by the controller 7 directly to the safety unit 9 Then, based on the flow shown in FIG. 5, the abnormality detection of the encoder 5 is performed.

As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately made.

For example, the first and second embodiments may be configured as follows.

-Modification (1)-
FIG. 9 is a block diagram showing a configuration of a robot control unit according to the modification (1).

In FIG. 9, in addition to the configuration of FIG. 6, a primary delay filter 22 as a delay control filter in consideration of a general control delay is provided between the controller 7 and the safety unit 9. Needless to say, the first-order lag filter 22 shown in FIG. 9 can be applied to the configuration shown in FIG.

In the actual control of the robot A, the rotational position (motor command position) of the motor 4 based on the command position information obtained by the safety unit 9 from the controller 7 and the safety unit 9 from the encoder 5 when compared in the same time There is a possibility that the rotational position (motor detection position) of the motor 4 may be deviated based on the output signal or the like. This occurs, for example, due to the nature of motor control. Specifically, after the controller 7 of the robot control unit 2 outputs the speed command and the command position information, the servo driver 10 actually controls the motor 4 and the motor 4 operates based on the control, so the constant time This is because a delay of

FIG. 10 shows the relationship between the motor command position (thick solid line in FIG. 10) and the motor detection position (thin solid line in FIG. 10) when the joint shaft 12 of the robot arm 11 is reciprocated at the maximum speed. It is. When the thick solid line and the thin solid line in FIG. 10 are compared, a delay of about 0.1 second occurs at the maximum, and a delay of about 18 degrees occurs in terms of angle (see the dashed line in FIG. 10).

On the other hand, it is understood that the difference between the motor command position and the motor detection position is largely reduced by providing the first-order lag filter 22 as shown by the broken line and the two-dot chain line in FIG. In FIG. 10, a broken line indicates a motor command position according to the configuration of FIG. 9, and a two-dot chain line indicates a deviation between the motor command position and the motor detection position according to the configuration of FIG.

With the configuration as shown in FIG. 9, it is possible to determine the abnormality of the encoder with higher accuracy than in the configuration of FIG. 2 or the configuration of FIG. Specifically, for example, the predetermined threshold value Pth used to compare the detected position information and the commanded position information may be determined based on the difference between the motor commanded position and the motor detected position. In this case, by reducing the difference between the motor command position and the motor detection position, the predetermined threshold value Pth can be reduced, and as a result, the abnormality detection accuracy of the encoder can be enhanced.

In addition, since the abnormality detection method of the encoder 5 may be performed in the same manner as the procedure using FIG. 5, the detailed description thereof is omitted here.

-Modification (2)-
FIG. 11 is a block diagram showing a configuration of a robot control unit according to the modification (2).

In FIG. 11, in addition to the configuration of FIG. 9, a damping filter 21 connected in series to the first-order lag filter 22 is provided between the controller 7 and the safety unit 9.

As described above, in actual control of the robot A, high response control may be performed depending on the contents of operation control of the servo driver 10. For example, in a welding robot using a laser, high-speed control and control with improved trackability can be performed. When such high responsiveness control is performed, the motor 4 may vibrate due to the excitation component included in the command position information. Therefore, in order to suppress the vibration of the motor 4, a damping filter (not shown) is often used between the servo driver 10 and the motor 4. Therefore, when the above-described high responsiveness control is performed, a command similar to the control by the servo driver 10 can be generated by adopting the configuration as shown in FIG.

FIG. 12 is a diagram showing the relationship between the motor command position and the motor detection position when the joint shaft 12 of the robot arm 11 is reciprocated at the maximum speed. The thick solid line and the thin solid line are the same as FIG. 10, and show the operation according to the configuration (see FIG. 2) in which the first-order lag filter 22 and the damping filter 21 are not used. Further, in FIG. 12, the broken line indicates the change of the motor command position according to the configuration of FIG. 11, and the two-dot chain line indicates the deviation between the motor command position and the motor detection position according to the configuration of FIG. From FIG. 12, it is understood that the difference between the motor command position and the motor detection position is further reduced by providing the damping filter 21 in addition to the first-order lag filter 22.

Therefore, with the configuration as shown in FIG. 11, it is possible to determine the abnormality of the encoder with higher accuracy than in the configuration of FIG. 2 or FIG. Specifically, for example, as in the modification (1), the predetermined threshold Pth can be reduced, and as a result, the abnormality detection accuracy of the encoder can be enhanced. The damping filter 21 is for removing the resonance component from the inputted command position information. Further, both the damping filter 21 and the first-order lag filter 22 may be directly provided in random order, or only one of them may be provided.

In FIG. 11, the positions of damping filter 21 and first-order lag filter 22 may be interchanged with each other, and the same effect can be obtained.

-Modification (3)-
Further, in the abnormality determination method according to FIG. 5, the flow as shown in FIG. 13 may be used. In FIG. 13, the processes according to steps ST1 to ST6 are the same as those in FIG. 5, and thus the detailed description thereof is omitted here.

In FIG. 13, when the difference between the motor command value and the motor detection value is equal to or more than a predetermined value in step ST7, that is, when the result of step ST7 is "YES", the process proceeds to step ST8. Then, in step ST8, the CPU 92 of the safety unit 9 determines whether or not the controller 7 instructs an emergency stop of the robot A.

Specifically, the controller 7 outputs an emergency stop signal (not shown) to the safety circuit 6 when stopping the robot A in an emergency. The safety circuit 6 having received the emergency stop signal shuts off the driving power supply of the robot A, and stops the robot A. In the present modification (3), the safety unit 9 acquires an emergency stop signal from the controller 7. Then, in step ST8, it is determined whether or not the emergency stop signal is output from the controller 7. If the emergency stop signal is output from the controller 7 (YES in ST8), the flow returns to step ST3. That is, even when the difference between the motor command value and the motor detection value is equal to or more than the predetermined value, it is not determined that the encoder 5 is abnormal.

On the other hand, when the emergency stop signal is not output from the controller 7 (NO in ST8), the process proceeds to step ST9. In step ST9, the CPU 92 of the safety unit 9 transmits an emergency stop signal to the safety circuit 6, and the safety circuit 6 having received the emergency stop signal stops the robot A in an emergency.

As described above, by performing the process of step ST8 after step ST7, the safety unit 9 does not erroneously determine that the encoder 5 is abnormal when the emergency stop is instructed by the controller 7. Specifically, when the controller 7 stops the robot A by outputting an emergency stop signal, the output of the command position information of the controller 7 is stopped. For this reason, when the comparison between the motor command value and the motor detection value is continued in the safety unit 9, there is a possibility that it will be judged as abnormal although the encoder 5 is operating normally. However, the occurrence of such a problem can be prevented by performing the process according to this aspect.

In the flows of FIG. 5 and FIG. 13, the steps need not necessarily be processed in the order described, but if the order can be changed or parallel processing can be performed, the order of processing and the processing method are appropriately selected. You may change it. For example, the process according to steps ST3 and ST4 and the process according to step ST5 may be performed in parallel.

-Third embodiment-
In the present embodiment, a method of detecting an abnormality of an encoder related to the continuous operation of the robot A will be described.

Even when the robot A is operated continuously, the basic configuration and operation are the same as in the first embodiment, and the detailed description thereof is omitted here, and the parts related to the continuous operation are described in detail. Do.

FIG. 14 shows the motor command positions P1 to P3 in the case of the so-called progressive operation in which the motor command position sequentially moves from P1 to P2 to P3 based on the speed command from the controller 7, and The relationship with the position Pr of the motor (hereinafter also referred to as the current position Pr) is shown. In the advancing operation as shown in FIG. 14, when the motor command position has moved to P3, the current position Pr exists in the vicinity of P3. Therefore, the abnormality of the encoder 5 can be detected by performing the process according to the flow of FIG. 5 or FIG.

On the other hand, as shown in FIG. 15, the so-called reciprocation that the motor command position based on the speed command from the controller 7 sequentially moves from P1 to P2 via P2 to P3 and then returns to P1 via P2 In this case, the safety unit 9 may erroneously determine that the encoder 5 is abnormal. For example, when the reciprocating operation of FIG. 15 is performed at high speed, for example, the servo driver 10 causes the motor 4 to start an operation before the current position Pr of the motor 4 reaches or sufficiently approaches P3. Pr may return from P2 to P1. In such a case, when the safety unit 9 compares the motor command position based on the command position information P3 with the motor detection position based on the current position Pr of the motor 4, the difference between the position P3 and the position Pr is large. Due to the above, there is a possibility that the safety unit 9 will be determined as abnormal although the encoder 5 is operating normally.

Therefore, in step ST5 in FIG. 5 and FIG. 13, the CPU 92 integrates the change amount .DELTA.n of the motor command value (difference amount .DELTA.n from the immediately preceding command position) based on the command position information for a predetermined n times (for example, 5 times). Do the processing. Specifically, for example, when reciprocating from the point P1 to the point P9 as shown by a solid line in FIG. 16, five times from Δ1 to Δ5 are integrated. That is, the integrated value Δ is Δ = Δ1 + Δ2 + Δ3 + Δ4 + Δ5. FIG. 16 is a view showing a motor command position when the joint shaft 12 of the robot arm 11 is reciprocated.

Furthermore, in step ST6, the CPU 92 compares the value obtained by increasing or decreasing the integrated value Δ to the motor command value with the motor detection value calculated based on the detection position information, and in step ST7, based on the comparison result. It makes it possible to determine an encoder error. Specifically, when the motor detection value P (fs) satisfies the condition of the lower (Equation 1), it is not determined that the encoder 5 is abnormal. At this time, the amount of change Δn is integrated as an absolute value regardless of the direction of the change. Further, the amount of change Δn changes in accordance with the speed of the motor, and is proportional to the speed. That is, when the drive of the motor is at high speed, the change amount Δn has a large value. Conversely, when the drive of the motor is at a low speed, the change amount Δn has a small value.

This makes it possible to prevent the CPU 92 from determining that there is an abnormality despite the fact that the encoder 5 is operating normally in a specific robot operation method such as reciprocating operation.

When the abnormality detection method of the encoder 5 as described above is adopted, for example, the integrated value Δ may become 0 during a period in which the robot A does not operate for a predetermined period in an emergency stop. Therefore, in step ST5, a predetermined threshold value Th may be added to the integrated value Δ as shown in (Equation 2) below instead of (Equation 1) above.

When there is no change in the command position information from the controller 7 for a predetermined period, there is a period in which the controller 7 instructs the robot A not to move for a predetermined period. In the above case, by providing the threshold value Th, the safety unit 9 can detect an abnormality even when the robot is performing an unintended operation of the control device, and the operation of the robot A can be stopped in an emergency. It will be.

It goes without saying that the new command position information shown in FIGS. 4A, 4B, 8B and 8B is also included in the command position information in the modified examples (1) to (3) and the third embodiment.

Further, in the first embodiment, although an example in which the difference signal from the position sensor 13 is input to the servo driver 10 has been described, the present invention is not particularly limited thereto, and may be input to the controller 7. For example, in the flow shown in FIG. 4A, step ST1 is followed by a step in which the controller 7 takes in the difference signal from the position sensor 13, and based on this, the command position information generated in step ST2 is corrected. Good. That is, when the servo driver 10 controls the motor 4 based on the speed command, the output signal, and the difference signal from the position sensor 13, the controller 7 receives the difference signal from the position sensor 13, while the difference in command position information A correction value obtained by converting a signal is added to generate new command position information, and the new command position information is transmitted to the safety unit 9. Further, in this case, since steps ST4 to 8 shown in FIG. 4A are omitted, the procedure of transmitting the command position information to the safety unit 9 can be simplified, and the time until transmission can be shortened.

The controller information transmission method of the present disclosure can prevent erroneous detection of an encoder abnormality when the servo driver controls the motor also based on information other than the main speed command from the controller and the output signal from the encoder, and Since the encoder abnormality detection method can determine the encoder abnormality by minimizing the influence on the existing function and the existing device even when using a general-purpose encoder, an industrial robot such as a general-purpose welding robot or It is particularly useful in determining abnormalities in encoders associated with other actuators.

A robot (actuator)
W Work 4 Motor 5 Encoder 7

Controller

8, 93 RAM (storage unit)
9 Safety unit (error detection device)
10 servo driver 12 joint axis (output axis)
13 Position Sensor 21 Damping Filter 22 First Order Delay Filter (Delay Control Filter)
92 CPU (judgment unit)
94 Encoder Receiver (First Receiver)
95 DPRAM (second receiver)

Claims

A method of transmitting information from a controller provided in an operating device for processing a work, comprising a robot arm and a motor connected to an output shaft of the robot arm,
The controller outputs a speed command instructing a rotational position of the motor and command position information indicating a rotational position of the motor according to the speed command.
The actuating device is
An encoder for detecting the rotational position of the motor;
A position sensor that outputs the displacement amount of the work from a predetermined position as a difference signal;
It controls the driving of the motor based on at least the speed command and the output signal, receiving the speed command output from the controller, an output signal output from the encoder, and the difference signal output from the position sensor. With the driver
And an abnormality detection device that detects an abnormality in the encoder.
When the driver controls the motor based on the speed command, the output signal, and the difference signal,
While the driver transmits the difference signal to the controller, the controller adds a correction value obtained by converting the difference signal to the command position information to generate new command position information, and detects the abnormality. And transmitting the new command position information to the device.
A method of transmitting information from a controller provided in an operating device for processing a work, comprising a robot arm and a motor connected to an output shaft of the robot arm,
The controller outputs a speed command instructing a rotational position of the motor and command position information indicating a rotational position of the motor according to the speed command.
The actuating device is
An encoder for detecting the rotational position of the motor;
A position sensor that outputs the displacement amount of the work from a predetermined position as a difference signal;
It controls the driving of the motor based on at least the speed command and the output signal, receiving the speed command output from the controller, an output signal output from the encoder, and the difference signal output from the position sensor. With the driver
And an abnormality detection device that detects an abnormality in the encoder.
When the driver controls the motor based on the speed command, the output signal, and the difference signal,
The driver generates target position information based on the difference signal and the speed command and transmits the target position information to the controller, while the controller transmits the target position information as new command position information to the abnormality detection device. Method of transmitting information on a controller characterized by
A method of transmitting information of a controller provided in an operating device comprising: a robot arm; and a motor connected to an output shaft of the robot arm,
The controller outputs first and second speed commands for instructing the rotational position of the motor and command position information indicating the rotational position of the motor according to the first and second speed commands.
The actuating device is
An encoder for detecting the rotational position of the motor;
Receiving the first and second speed commands output from the controller and an output signal output from the encoder, and driving the motor based on at least one of the first and second speed commands and the output signal Driver to control the
And an abnormality detection device that detects an abnormality in the encoder.
When the driver controls the motor based on the first and second speed commands and the output signal from the encoder,
The driver transmits control information based on the second speed command to the controller, while the controller adds a correction value obtained by converting control information based on the second speed command to the command position information. And generating new command position information and transmitting the new command position information to the abnormality detection device.
A method of transmitting information of a controller provided in an operating device comprising: a robot arm; and a motor connected to an output shaft of the robot arm,
The controller outputs first and second speed commands for instructing the rotational position of the motor and command position information indicating the rotational position of the motor according to the first and second speed commands.
The actuating device is
An encoder for detecting the rotational position of the motor;
Receiving the first and second speed commands output from the controller and an output signal output from the encoder, and driving the motor based on at least one of the first and second speed commands and the output signal Driver to control the
And an abnormality detection device that detects an abnormality in the encoder.
When the driver controls the motor based on the first and second speed commands and the output signal from the encoder,
The driver generates target position information based on the first and second speed commands and transmits the target position information to the controller, while the controller generates new command position information based on the target position information, and detects the abnormality. And transmitting the new command position information to the device.
An abnormality detection method for detecting an abnormality in an encoder for detecting a rotational position of a motor driving an output shaft of an actuator.
The actuating device is
An abnormality detection device that detects an abnormality of the encoder;
The information transmission method according to any one of claims 1 to 4, further comprising: outputting a speed command instructing a rotational position of the motor, and command position information indicating a rotational position of the motor according to the speed command according to any one of claims 1 to 4. A controller that sends to the anomaly detection device;
And a driver that receives the speed command output from the controller and an output signal output from the encoder, and controls driving of the motor based on the speed command and the output signal.
The abnormality detection device is
An information acquisition step of acquiring the command position information from the controller and the output signal from the encoder;
The command position information and the detected position information of the motor calculated based on the output signal are compared, and when there is a difference of a predetermined value or more between the command position information and the detected position information, the encoder A method of detecting an abnormality in an encoder, comprising the steps of: determining an abnormality;
The abnormality detection device receives, from the controller, command position information in which a time delay due to a delay in drive control of the motor is compensated, and in the abnormality determination step, the command position information in which the time delay is compensated and the detection The encoder abnormality detection method according to claim 5, wherein the presence or absence of an abnormality of the encoder is determined based on a comparison result with position information.
The abnormality detection device receives command position information from which the resonance component has been removed from the controller, and in the abnormality determination step, based on a comparison result between the command position information from which the resonance component has been removed and the detection position information. The method for detecting an abnormality in an encoder according to claim 5 or 6, wherein presence or absence of an abnormality in the encoder is determined.
The abnormality detection device generates an integrated value of change amounts of the command position information output from the controller in the abnormality determination step, and compares the sum of the integrated value and the command position information with the detected position information. The encoder abnormality detection method according to any one of claims 5 to 7, wherein presence or absence of an abnormality of the encoder is determined based on a result.
The abnormality detection device determines presence / absence of abnormality of the encoder based on a comparison result of the sum of the integrated value and the command position information plus a predetermined threshold and the detection position information in the abnormality determination step. The method according to claim 8, characterized in that the determination is made.
There is further provided a safety circuit for emergency stop of the actuating device,
The controller is configured to transmit an emergency stop signal to the safety circuit in an emergency,
When the abnormality detection device detects that the emergency stop signal has been output from the controller in the abnormality determination step, a difference of a predetermined value or more exists between the command position information and the detection position information. The encoder abnormality detection method according to any one of claims 5 to 9, wherein the encoder abnormality is not determined to be the encoder abnormality.